Method of making color reproductions



May 30 1944- A. R. BOURGES 2,349,900

- METHOD OF MAKING COLOR REPRODUCTIONS Filed June 10, 1940 BY KM Patented May 30, 1944 METHOD F MAKING COLOR REPRODUCTIONS Albert R. Bourges, New York, N. Y. l Application June 10, 1940, Serial No. 339,604

8 Claims.

This invention relates to the graphic arts, and relates more specically to an improved process for making reproductions of drawings, photographs and the like, particularly wherein the reproduction is to be made in one or more colors from black and white copy, particularly in that photography is eliminated, except for the key plate, and all color plates are made from contact prints.

One of the principal objects of the present invention is the provision of an improved process for making color reproductions at a considerably lower expenditure of time and cost than with existing methods, the process also being characterized by its marked simplicity as compared with known methods of color reproduction.

In accordance with the existing practices in this art, the artist usually prepares the copy in black and white, and in some ca ses also prepares a transparent flap showing a suggested color scheme. The photo-engraver or lithographer produces a line reproduction from the black and white drawing from which a proof is made 'for the color scheme in the event that no color flap is supplied.

Following this a print on metal is made for each color in addition to the black, and upon the individual color plates the desired tints and tone values are applied by the well known transfer methods. These methods require a considerable expenditure of time and the cost is exceedingly heavy since a high order of skill is required in laying the tints in an artistic fashion. The method of the present invention, as will become apparent hereinafter, may be employed in slightly varying form in virtually all branches of the graphic arts. This method will now be generally described by way of illustration in -connection with the preparation of color plates for color comics.

A print of the negative of the black and white copy is first made upon the sensitized metal plate, and before the same is etched, a thin, transparent sheet of celluloid, cellulose acetate, or other similar material is placed over the print on the metal,

Athe same being optically visible and in reverse.

This sheet will be hereinafter referred to as the color guide and protecting sheet. The worker then indicates the desired color scheme on this color guide and protecting sheet.

The next step is to place over the color guide sheet a sheet of seasoned, highly transparent cellulose acetate which will be hereinafter referred to as the color negative sheen 0n this latter sheet he outlines al1 of the areas he desires to 55 reproduce in a given color. In accordance with existing practices, he usually prepares the color negative sheet for yellow in the first instance,

and then proceeds to aillx his desired tints to these areas in the following manner.

A shading sheet of the type described in my co-pending application Ser. No. 339,603, filed June 10, 1940, is cut or rubbed to a size generally conforming to the outlined area or areas. This shading sheet consists of a transparent carrier sheet of cellulose acetate or other suitable material upon which has been imprinted half-tone, Ben Day, or character effects, the ink used in printing such effects being of a color which is transparent to the eye and opaque to the camera.

This type of shading sheet possesses many advantages over the earlier transparent shading sheets made in accordance with Patent No. 1,614,924 wherein the character effects were imprinted with a b1ack,`opaque ink. It will be apparent, however, that the present invention is not dependent for success upon the improved shading sheets described in my co-pending application, since good results can be obtained by the use of the earlier type of shading sheets, except in the heavy tones wherein the improved sheet is vastly superior.

In the event that several areas are to be tinted with the same color, a single shading sheet can be placed over the several areas, and in this instance it is not necessary to remove the detail lying outside the outlined areas since the outline serves as a guide for the router who removes all excess metal lying outside such outline areas, except those portions needed for barriers.

The color negative sheet for the rst color may now be removed from the color guide sheet, and the successive color negative sheets prepared in the same fashion. From these color negative sheets prints are made on the sensitized metal and the plates are etched, routed and finished in the usual manner.

- 'I'he advantages of the foregoing method over methods of the prior art are numerous, as will be appreciated by anyone skilled in the art. For

instance, the several color negatives can be checked before the plates are made by superimposing the color negative sheets one on top of `the other in register. l'n this manner any moire effect or misses will be readily apparent and can be easily corrected before the plates are made.

Another particular improvement in the present process resides in the fact that the etching is made from a uniform photographic resist and not a transfer resist as in the case of the Ben Day process. Another advantage in this method is in the fact that the work is done directly over the color guide and the print on the metal, and there is accordingly no danger that the areas to be colored will become distorted, nor is there any opportunity y for imperfect register. Moreover, one always obtains exactly the same size and shape of mask, and if for any reason there is a movement or distortion while working over the color guide and the metal, it will be readily noticeable before the color negative is lifted E.

Yet another object of the invention is the pro vision of an improved process which can be employed in connection with the Ben Day method of shading wherein added modeling may be transferred directly onto either side of the shading sheet which will give the finished results the superior features of both methods, it being understood, of course, that this creates a negative that gives a photgraphic print and photographic resist onto the plate, and not the transfer resist of the original method.

A still further object of the invention is the provision of improved means for following the color guide now in use by photengravers and lithographers in a more accurate manner than is now possible by the Ben Day or other process working lfrom black and white copies, and vrto accomplish such result in a much shorter time than can be done by existing practices. In other words, the work is done directly over the color scheme, and it is not necessary to refer to the color scheme sheet located at a point spaced from the work.

A still further object of the invention is the provision of an improved method of making color reproductions wherein the tone values can be standardized; that is to say, precisely the same tone value can always be recreated without any variation whatsoever, since the shading sheets have a fixed tone value, whereas in the Ben Day method the tone value varies according to the amount of ink used in rolling up and the amount of pressure used in transferring the ink.

'I'he method constituting the present invention has been discussed in connection with therreproduction of color comics and like copy. Another and particularly important use of the method is in connection with the process of adding color to newspaper advertisements where the originals have already been made or printed in black or one color only. In other words, the method in this connection facilitates the use of color in cases wherein black only is used, and wherein the use of color would be prohibitive from the standpoint of time and cost.

In this connection, any newspaper copy, which may be a group of different illustrations that could not be photographed together, but which for obviousreasons was required to be assembled in combination with type message, can be used as a composite copy for making color plates in one piecev to nt the entire page after the same has been printed upon metal. After this printing upon the metal the same method as for the color comics is followed. In other words, the procedure in this case is tewerk over a print on metal from the composite set-up, all other steps thereafter being similar, except that distinctive character effects having definite advertising or trade-mark value to the advertiser can be added.

'I'he simplicity and speed of this method makes it possible for color plates to be prepared more quickly than the black and white plates, particularly if a second print is made, and may be worked over while the original plate is etched and routed.

The several steps in carrying out the method of the present invention are illustrated in the drawing, in which:

Fig. 1 is a copy in line to be reproduced in color, this figure as well as the other gures having the conventional registration marks for registering colors.

Fig. 2 shows the copy after the same has been treated with a shading sheet to create a gray fur eiiect in the collar of the coat.

Fig. 3 is a print of the copy in reverse on metal with color notations marked on the color guide and protecting sheet which overlays the metal plate.

Fig. d is similar to Fig. 3 but shows the color .negative sheet overlaying the color guide sheet,

the view also showing the area outlined for the red or flesh tint on the negative sheet, and the shading sheet positioned over such area.

Fig. 5 shows the color negative sheet, overleying the reverse print and color guide, outlined and left blank so as to create a solid yellow plate for the green coat and hat.

y Fig. 6 is outlined similar to Fig; 5 and includes a shading sheet breaking up the solid areas, creating a lighter tone of blue which will give a yello green coat and hat.

The copy I0 in Fig. 1 is a line drawing, and since a gray tone is desired in the coat collar tI, this tone is incorporated in the copy. as shown in Fig. 2, by the use of a shading sheet so that it comes in the negative and will print in the black plate. The copy is now photographed in the usual manner, creating a negative which is printed in reverse on the sensitized metal I2.

Over the print on the metal the color guide sheet I3 is placed (Fig. 3), such sheet, as aforesaid, being transparent and being .adhesively secured to the metal print in any suitable manner. Upon this color guide sheet the various color designations are written in the manner shown. This designation may, of course, be made by actual colors. The rst transparent color negative sheet I4 is now placed over the color guide sheet (Fig. 4), and the face is outlined in black ink with fountain pen as indicated at I5, thus defining thearea to which the red or esh-colored tint is to be applied.y The shading sheet I6 is now placed over this area and is adhesively secured thereto.

The negative for the red plate is marked with a plurality of crosses outside the area defined by outline I5 to indicate to the router that such is the waste metal section, and the outline I5`constitutes the guide for routing the face to shape, which line I 5 comes white when etched.

In Fig. 5 the negative sheet I4 has been removed, and a second negative sheet 20 has been placed over the color guide sheet I3 in the manner previously described. In the present instance. negative sheet 20 is used for making the. color plate for yellow, and' in this case the yellow is to be a solid tint for the coat defined by the outline 2I, and the hat defined by the outline 22. Outside of these areas the waste metal areas are again indicated by the cross marks, and the areas inside of outlines 2| and 22 are left clear.

Negative sheet 20 is now removed, and negative sheet 24 is placed over color guide I3, as shown in Fig. 6. This negative sheet is outlined exactly the same as negative sheet 20 for the yellow plate, there being provided the outline markings 25 and 28 around the coat and the hat, respectively.

2,349,900 'Since negative sheet 24 is used for producing the blue color plate, and since a lighter tone of blue is desired than for the yellow, a shading sheet 21 is placed over these areas to reduce the color concentration. It will be appreciated that there is no additional work done upon the shading sheet beyond placing the same over the outlined sections.

The steps in the process just described are illustrative of one method of carrying out the present invention, and the many variations of the process will accordingly become apparent to those skilled in the art. The printing of the copy, from a negative` thereof, onto the printing plate is essen.-

` tially the rst step in the method. The copy may be a line drawing, a wash drawing, a photograph, or a combination of any or all of the three. In

the case of the line drawing, it is frequently desirable to add detail or modeling thereto bytreating it with one or more shading sheets before photographing. This is usually done for modeling in grays or browns. Wash' drawings or photographs are reproduced in half-tone on the sensitized metal plate, and in this instance also the present process begins when the drawing or photograph has been printed on the sensitized metal plate.

The second step is in superimposing the color guide sheet and the color negative sheet, both transparent, over the print on metal. In some instances the color guide sheet may be eliminated, although this is not practicable since the process is greatly facilitated by the color guide sheet being interposed between the print andthe negative sheet, thus eliminating constant reference to a color 4guide placed elsewhere. If desired, the negative sheet can also be eliminated since the outline can be made directly on the shading sheet, which, of course, is transparent. This also is not practicable for most cases.

The shading is used only in cases wherein character or different tone values are desired, and is not necessary `in cases wherein solid tints or colors are needed. These are obtained merely by outlining pn the negative sheet or seasoned transparency. Whether the negative sheet or the shading sheet is used alone, or in combination, there is the great advantage in this method of perfect register, since the single or composite negative sheet, with the outline guide thereon, is lifted from the key plate and printed through on the similar metal in precisely the same position.

In offset work with the albumen type of plate, a negative of the copy, i. e., line drawing, wash drawing, photograph, or combination thereof, is made inthe usual manner, and such negative is printed onto the sensitized lithographic plate. The resulting print is the same as the print by the photo-engraving method, except that there is no reversalfrom left to right. Where a deepetched lithographic plate is used all prints, including the key plate, are made from positive values, and by this method the print on the metal is also positive in value. In other words, I do not outline in black on the negative sheet but use it only as a base for painting in where solid blacks are wanted, and attaching shading sheets which have been cut or rubbed to shape for desired colors. The expression negative sheet when used in connection withthe deep etched lithographic process is, strictly speaking, not a negative but a positive-value transparency, although the expression negative sheet is used herein since its actual photographic value, that of a positive transparency, is well recognized in the lithographic art. Accordingly, when the word negative is used in the appended claims in connection with the method as applied to deep etched lithographic work, such Word is deemed to 5 mean a positive transparency.

In the case of gravure color work where positives in full tone value are needed, to be afterwards screened a half-tone, a translucent shading sheet, of the type described in my aforesaid copending application, ranging in tone values from pure white, or possibly to solid, can be rubbed or cut to shape, thus creating any range of color value. Here again I work with positive values instead of negative Values.

Composite newspaper advertisements in black and white only have been previously mentioned. The application of color to such advertisements has heretofore been limited in view of the time and cost elements involved. By following the method of the present invention the color plates can be made from the composite print of the black and white page as a guide. In other words,

no `additional photographing is necessary, and I do not add to the cost of the original blackl plate, the additional cost being only that of the color plates made by direct contact, thus eliminating photography and Ben Day.

In silk screen work the positive valueprinciple, the same as for gravure and deep-etched lithographic plates, is used. In other words, where the detail of the shading sheet is a black dot this positive value retards the light when used over the sensitized silk screen, carbon tissue or other photographic material, the light making the 3a portion around the dot insoluble but leaving the dot soluble so that it will wash away, allowing the ink in silk-screen printing to come through. In this way endless Ben Day, half-tone and character effects can be incorporated photographically in silk screen work.

What I claim is:

1. The method of forming printing plates for making color reproductions'of line copy, wash drawings, photographs, or combinations thereof, which consists in the steps of forming a negative of the copy, printing the negative on a sensitized metal plate, placing thereover-a plurality of superimposed transparent sheets, marking color notations on the first sheet constituting a color guide sheet, tracing on the second sheet the outlines of areas on the print to be reproduced in color, adding detail to desired portions of such areas by applying thereto a transparent shading sheet having detail thereon, and then producing a printing plate using the transparent sheet and attached shading sheet as a negative.

2. The method of forming printingplates for making color reproductions of black and white copy which consists in the steps of treating the copy for black and brown tone values, forming a negative of the copy, printing the negative on a sensitized metal plate, superimposing on the print a color guide sheet, successively superimposing,

thereover for each color to be reproduced, a color negative sheet and a shading sheet, marking color notations on the color guide sheet, outlining areas to be colored on the negative sheet, and then forming a positive printing plate from the outlined areas on the negative sheet and the shading sheet, and removing metal therefrom outside said outlined areas, d

3. The method of forming printing plates for making color reproductions of drawings and the like which consists in the steps of forming a negative of the drawing, printing the negative on a sensitized metal plate,'superimposing on the print a plurality of transparent sheets constituting a color guide sheet, and a color negative sheet, marking color notations on the rst sheet, outlining areas' to be colored on the second sheet, and then forming a positive printing plate from the outlined areas on the negative sheet.

4. The method of forming printing plates for making color reproductions of black and white copy which consists in the steps of forming a negative of the popy. printing the negative on a sensitized metal plate, superimposing on the print a plurality of transparent sheets constituting a color guide sheet, a color negative sheetand a shading sheet, marking color designations on the iirst sheet, outlining areas to be colored on the second sheet, and then forming a positive printing plate from the outlined areas on the negative sheet and the shading sheet.

5. 'I'he method of forming printing plates for making color reproductions of black and white copy which consists in the steps of forming a negative of the copy, printing the negative on a sensitized metal plate, forming a plurality of color negatives for the several colors to be reproduced by successively superimposing on the print a plurality of transparent sheets constituting a color guide sheet, a color negative sheet and a shading sheet, marking color notations on the ilrst sheet, outlining areas -to be colored on the second sheet, and then forming a positive printing plate from the outlined areas on the negative sheet and the shading sheet, and repeating the process for each color plate.

6. That step in the art of reproducing copy in color which consists in laying a pluralityof transparent sheets over a print o! the copy on sensitized metal, before the same is etched, marking color notations on the lower sheet and tracing on the upper sheet outlines of the areas to be printed in a given color, and then making a color printing plate employing the outlined transparent sheet as a negative.

7. That step in the art of reproducing copy in colorwhich consists in laying a transparent sheet over a print of the copy on sensitized metal. before the same is etched, marking color notations on such sheet, laying a second transparent sheet over the rst sheet, and tracing on the second sheet outlines of the areas to be printed in a given color, adding detail to desired portions of such areas by ailixing thereto transparent shading sheets having the detail thereon, and leaving blank such areas as are desired in solid tints. and then making a color printing plate employing the outlined ltransparent sheet and the amxed shading sheet as a negative.

8. The method of forming albumen-type, lithographic printing plates for making color reproductions of copy, consisting of line drawings, wash drawings; photographs or combinations thereof, which method consists in the steps of forming a negative of the copvy printing the negative on a sensitized printing plate, placing thereover a plurality of superimposed transparent sheets, marking color notations on the rst sheet constituting a color` guide sheet, tracing on the second sheet the outline of the area on the print to be reproducedl in color, and then producing a printing plate using the second transparent sheet as a negative.

. ALBERT R. BOURGES. 

